package com.kuang;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;

public class DownServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        super.doGet(req, resp);
//        1.获取下载文件的路径
        String realPath=this.getServletContext().getRealPath("/WEB-INF/classes/鸡肉.jpg");
        System.out.println(realPath);
//        2.下载文件名是啥
        String fileName=realPath.substring(realPath.lastIndexOf("/")+1);
//        3.让浏览器下载东西
        resp.setHeader("Content-Disposition", "attachment; filename="+ URLEncoder.encode(fileName,"utf-8"));
//        4.获取下载文件的输入流
        FileInputStream in=new FileInputStream(realPath);
//        5.创建缓存区
        int len = 0;
        byte[] buffer = new byte[1024];
//        6.获取OutputStream对象
        ServletOutputStream out=resp.getOutputStream();
//        7.将FileOutputStream流写入到buffer缓冲区，使用OutputStream将缓冲区中的数据输出到客户端
        while( (len=in.read(buffer) )>0){
            out.write(buffer,0,len);
        }
        in.close();
        out.close();
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}
